How does this work in practice? Is the behavior of a use-after-free defined? Data races? The latter even more so for objects that don't fit in one machine word, such as slices.
While avoiding undefined behavior is a noble goal, my personal feeling is that actually achieving that will be much harder than it might first seem, and will probably end up precluding a good deal of optimization.
Of course, C has an entire class of UB that is much more excessive than useful, for example left shift of a negative integer. It's clearly and obviously possible to do much better than C. I'm just skeptical that "no UB at all" is in reach for a low-level, systems programming language that is also portable and can be compiled with optimization comparable to C.
While avoiding undefined behavior is a noble goal, my personal feeling is that actually achieving that will be much harder than it might first seem, and will probably end up precluding a good deal of optimization.
Of course, C has an entire class of UB that is much more excessive than useful, for example left shift of a negative integer. It's clearly and obviously possible to do much better than C. I'm just skeptical that "no UB at all" is in reach for a low-level, systems programming language that is also portable and can be compiled with optimization comparable to C.